A low phase noise LC‐VCO for phase‐locked frequency synthesizers

ABSTRACT This article presents a low phase noise voltage‐controlled‐oscillator (VCO) using standard 0.18 um RF CMOS process. This VCO is based on the voltage‐biased technique with a tail‐current inductor. Design considerations toward low phase noise are given and some tradeoffs are also described. Measurements show that the VCO has a phase noise of −49.8 dBc/Hz at 1 kHz offset and −134.8 dBc/Hz at 1 MHz offset from the 1.49 GHz carrier frequency. Compared with some other recently reported current‐biased and voltage‐biased VCOs, this work shows a better phase noise performance with reasonable power consumption. This VCO has been successfully applied in phase‐locked frequency synthesizers. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1486–1492, 2014